SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10c29912cc798d9b02242d4e4b034c30758df87caa10d3737260c54a29170b88' 
  AND token = '4ASvqjCIvT/KgZssNFRstWdlwkEhzdGOpb35xjiqoJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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