SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c29dceaf86de0148c42672e9bad03088f5d4c8318b31e9ea9c55a4bfc13f3bc0' 
  AND token = 'BzdQIkQSnXi1WLJq52VxLPJmx0hdsrxNH/6shlXxw4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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