SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bc64cc9582f94f80964ecd6119a39709735dbebbb0cce7a58db1b25453cdada7' 
  AND token = 'zTlInvuQKGk4K+URkZlPVr2AmryM2kcKmP2x9mNQ0SA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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