SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c5eee15ff8c345136cfb9f9508977ea5b77a44c13d2b3d2193028392afa6bd5' 
  AND token = 'tdrqH6vyT6/mZ6tv/Ykel1RWQ6MBECHW6dFGMTPQfIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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