SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4178e45c5cc52067e2541cbebf7a7fe020fccc3a3ef6aa65a731862662711d9c' 
  AND token = 'mqveCPKpg+oM1yv1nK2NMq5uXGXmzAxklqenFl3aeRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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