SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2000e7c5cc75cd4f0e93b828fe9a9d18ea5dc95161646a485e0a0403a2b4880' 
  AND token = 'I2qJrkVQDcWXrC211Z8Dr9mljr6NHdNMIcrZ847ji5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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