SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb9be5061272aed53765b67759040eaca275de83460321c43264095ad78fb44a' 
  AND token = 'jZNGGjsWMyxKP1JhAyeDUE1wgYDHmh/S5NPb9t6cQVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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