SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a216197ee03e0370f6316ba259c5d125e3226b6731c4de5fcdb899c652d036b9' 
  AND token = 'JqLSKUlAcTUjtI0GaH+YBglFt5EhokD3UjoQPg4FRDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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