SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd695356d154f99d6339c3961474b25a68bebf82d0b14e7b7dc052efbb3e2b844' 
  AND token = 'rechT7A1lUrnGlQPEktPp/3aGXpTEhtDTqKMPN/hYdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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