SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '60f8d58fd989a5d4512f464c818903ff1c2efa3d12079641734e0a0c0574d264' 
  AND token = 'JCVCjhuS6//1aodAFX4rDZ6ScK79kgUgVohGwuFn+OQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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