SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a914344d98a319a2cefbfdc3a579b89d24a66ef57d3e00ce0759bffee3244333' 
  AND token = '8ViIOUO3JGrFERgdJ7kUrc0qDABk7Vqx0nVcX6K7CKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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