SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1567653699a88025c1b5a0b8cc9931d2025de7c21691c2de7faabbe8b5686146' 
  AND token = 'fftmELMW40wuNFhSgB0bRJLmy6IZz6MHzGHaRmYobCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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