SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5d5ab9b25dfed498d629ae440ed5e64a0495af889fb4614b7c96623a76a019c' 
  AND token = 'kOhY/ekzUp4a8pmkArd9gONG8VnF+EAgSNYf6xwqsYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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