SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db0929916fdd17eae00b0193a0d4e0d564051f76496231eb6f6a2ecef04b22e0' 
  AND token = 'S2H/nmV7bwK3kb5utqC//U0pVdON0GvGo4amkm+G0UM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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