SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a13ed67622318addf700fb14dc87ac67ceb6a0340b0ba564dce8751449c22e50' 
  AND token = '6jYNFhENnVp3pOId5Xni16o4vGpEhDkLwb/ZMnTUQw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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