SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ac881461efefdfa47473569fd8044f4fbfe9775a8080eda01c93c95559d3e52' 
  AND token = 'b76O9kyobcPFPU7+dpnVI8xUlcDTJW4jy7yPZ53BkaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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