SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50458e71cb58c93414dbb4ca3ba4587b09637816636b90b1471a6fee822a7ca7' 
  AND token = 'ekeZgHv9jWF5wt0n9BFksIdM2qZWQEfQtyEknSLEyAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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