SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a48da0ed79d8d9a6b4f3d8ab2206e85ac0862a6bfa4ff5ef04b007ff65031e5' 
  AND token = 'WKixJkLc3N2HdpAWLHTXfpAUWZNCLGvSOwqTNRmSjXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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