SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e67aa3858c44993ef0d389dd1e1770ce7625aca35aa19d55414e11e23b9e36a' 
  AND token = 'Aww0lhQIuVxlLe3n/lRgZRv9lZwFeqdjz7vwUqt8IaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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