SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c71218563bc2c734dd719a178aafba8ec3022dea788e1ab877713ef970b3703c' 
  AND token = 'rkpOztqf8jtqBSvZf36XcG3FDErJjMOsXB691kWxQyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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