SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03956186499c4dba73304564659ea13cf78413692134d463ae73cd1ddf617370' 
  AND token = 'dnaEewFu6GQYUqggiOKwNGKopZomvis0ySDxni3ue98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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