SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd555577041b9aac643a6a885762d2d38a8f1e65afd1cadf1729f7f7dd16d69cd' 
  AND token = '5I/CzjtNxh+dWPt+WZEIwNXTgF+y0O1jx4RKkuVRRJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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