SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8dd38eeb954992f9e83f0c04f179bdfd71be4e595e581e93967c149681077376' 
  AND token = 'xajP5erO/IXyKWjjKULCh0tY8glxtoQmM4zqmEZpsLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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