SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c78e12baf71ee067cf8bf7f87fff93a1a1c1470840368d14d8def2622858f33' 
  AND token = 'NK0Nw6lPFs0qwKWuuOe4KM43yis2uuRpALA8K6QgNUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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