SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd5575f400d28a668b5fda4d57d4abd351a8bb296bd442227671790377024219d' 
  AND token = '/dRqjFPyWJxB353ZhNDG9DVDGzToVhk+JP5HdaU3yL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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