SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bec27d19e614bec6718570795c58941a36d08920b7bc59dcdd087f25edf9ecc5' 
  AND token = 'W1QtUqfzWQF7DaQn3gldoFNYqJUVWipuxS+LRFnY7nQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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