SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f08f957e70781b69056d155b911fbddd8882701cde4444e02910a2d6e623500b' 
  AND token = 'VydX8vMyHYjxPwg5OzVSmoOOwYIR0Gv+1tLCLapoAMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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