SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '675fa574efa778713fb0defa8bfc08ccbb3026d02aa100a745b0a6e03f529366' 
  AND token = 'anma37wLlYYZpXCKYbXOVPufVl2cYDdFs1dV7VmiN5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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