SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5be96320f85e4cf266b6838a77bad3d90247f75df5ee39575acaa204fbce3a00' 
  AND token = 'FkFLFyLQJ5t+tSP+5gaxVpPspqHZlrOuPQxK587QNbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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