SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '39af212de673eed20db3b79b6299a65582245c63a6bf2cadba870f2b251cfe94' 
  AND token = 'VJJ4IlqTN4TvBuDti1Lk2IbkCjn4FfPliMRNifywQmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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