SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b42ac256380d32e4738a7b85ba29cd1dd2286202015fabc7f2aa7251d769398' 
  AND token = 'fd2pdpUTEyncWf0K0io3lG6x2r6pyn2vCDC0/cHIJWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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