SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2868cfae6364deaa72ad8ea1754fb031a75b45d90b37b54fb1db0881eb179b65' 
  AND token = 'aQgCcgQu17ilLe6hRovEp1SYwp3vBS2ur/Sa1WOnKJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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