SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '404473f63e905be215e6aecd166a7ebabbde93630e74311aba3c90dde525f19c' 
  AND token = 'dftk0Oi81tuGvGtYnl1BKQ7pFeiCrLdBOsME3bJEd6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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