SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '26e55a3f25841ce5800a8b4940636240b751d58fac6efa0dd8a52435ad7db079' 
  AND token = 'Cne3IfbGs1YtADviUKETeAzCBRu0FiQef8fKP2ReL7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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