SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea726314f0d4980fb59c47d575dce0f5b01e090fa13a432a6e01a2ad8e3d18be' 
  AND token = 'RSLJ7jz0v8qWVizK7wKlQ9BPqODAuFCHT3zGjemOiQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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