SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2686fc90a22244c846dd790b5afe43f545419db44294ececb41cc69afc19601' 
  AND token = '2cK0j/3o20Drw6npbhQRnZHQhJyPNtNAHfKntncipoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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