SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1064a78fc5e0c0673b1c9ea8f98265e77c6ef7a3ad3f32ee1d4c253b68694919' 
  AND token = 'J4HZztgu4ujoWuFQbAfsUIdRujcPwCiUCXv3WPNhn/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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