SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c0c28742cdb2e89329258ab871b38ac91f72692ea1640a675fa3b85856a3073' 
  AND token = 'Um3jN6Mo8M+UaPZGMXgDdMZedPlX/LsKziiJPVDQLGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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