SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a2c796442c81f629806f2832e499e3a32441ffc93ac987f9e1e304c4bf50f67' 
  AND token = 'EnoKW7tJQqHZ7XgfTS1Ecgnlk5QEpPBvWK6IohsB2ZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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