SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3f145d42930fab8ff348a49329369e5da43551cfb49db18a7c6c6bd1e438753' 
  AND token = 'mCVrY4VMYz1LPNsjfTmOb/PJqwFMD/zuVjSsmUU7YJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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