SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '385d367f464a55cf0ca232490f55c369417b4d7ca5c84f714bac104eae52c9bc' 
  AND token = '/TF3++bYVs/Kiu4DqQLhRp6JaDtC9JRFtjNsnRrFTHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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