SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6708374834030ea0a0629006acb03f0ef791893f227e8dca2bb0a983cf95760f' 
  AND token = 'OHiqNT0yQReEl/omS7DpjOtAo0zWKpeEMaoHtiH28Ec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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