SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15504587bea09872cb826c32e252390dca94033e3a393e014f61df051e3293cd' 
  AND token = 'cN/Wo8UNo6N0OcWF4le9gOLSPRjCDacniZ8c6SmGbsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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