SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b35810ec6b0eb672618a59e1243f09377f66bb637c1d4808f5eb6e679fce6467' 
  AND token = 'HiGPvqMKdTsbHJtIMk+CAPV93h2/I3RH5TqUHZ5m4bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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