SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16af380a91bd83c8e5501327da26bfc17afedf80eb57990dbf29ac25fa1b5cd5' 
  AND token = '3EB+Dqh17AfPexhyaODxJPhVDHsxdBv/9C9q4S+2i9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}