SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '778e8d265f53af8441b6cd4dbba1854ee9e088f5c1bd01fff07bfcffaee2ebf9' 
  AND token = 'sU9PoECmGoQojhMOTyXIJToRWYxPMFpW9sZOO+jAqao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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