SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cf7dd1f5587914fef808c811c0851868c29ccca1cb4b715758209ce100ce854' 
  AND token = 'smNjtT54TfnoTDX5ChargO4idSSa9VYhrPCuAFBD6fI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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