SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb89045f205019f5f7fadfdcd990fa8d2ded9373f646553caaf3a010ceb4eddf' 
  AND token = 'FjkH4/7wULxhFVuYEwviYyEF1Q7Gbp+K+edMG4Jw+Zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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