SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f78e008a8c038f92b3784e11df089c099b14f25015d2adebca4e1b1ef64a4f11' 
  AND token = 'cqfdDpqzjiG7exj4f3MnHeCm+Ddvm/uOD4WDAuQoCmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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