SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d574d2555fd8d0866433ade0ff90ae39940ac70ebe5fed9114e3aee750c16a5' 
  AND token = 'vOifWCR1Zyoaw/IK/8Yphxg5xntaS2x7YTvQ61h2Zpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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