SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b414c238c22d8a6b765002182e3fda1772156d81edbec5cb24157f9170752b0' 
  AND token = 'nKrP5TIph1peU5FLWFeI4oimbGTo0Kbfwqk5A5RdFuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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