SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85591cc1a8ed54329dcd5688ef82ee8765b5264d07624f504310e380d8fe9886' 
  AND token = 'bG5R3H1KzbyRqJ3BEcOmlpBMEzlokduoep0qeFs4/PI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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