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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be0eb15577494c667b2ec78b0917b7e73cbb6be1538c8ac05e34111ac9f0ae3a' 
  AND token = 'FBgjJRItkSrHaO8BJiDgFGCb8QJMPFZA/RI7o2Hjt/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}