SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '288f186574565589918689ba6310c2f3a293e48d544758c2af16fdb8ec8b4c2d' 
  AND token = 'LzTzAJjueLa7rmShAEnrr5ijMPfxXj/1/fUn+wGywoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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