SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0a9e725150d9d07be2b459612501f99fbb997b98042075c55a5881e795d3abf' 
  AND token = 'bDqw4QBjSYC0Ih6WES+uZQ4O7JNh7lxlQICUXCsClyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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