SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b27cf781d414ab0aedd862aace87a6abe59cc4b3107150c8d2dd5064ff43f963' 
  AND token = 'yaBIIVFRg2bfDB620vZEPiehDOep0UMFH2TqpUshoUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}