SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80703b0bf03c0b0785a68e98360572116c59fc0224dc786559734ccc930355de' 
  AND token = '3rG88hw7kfjblAbWuTL8CsV22+03ECdm9Khh8zNb5hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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