SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e301e1bba4b6f215b3ddbb777701c2a8645d4880315fd8552e9b3cbe56f61a2e' 
  AND token = 'OLPSmRh5jk7K3vL9tTJvQnwAqsH9zR7gw/oWP0oYA2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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