SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6400bd76edc5843ea26c038a00f669db1cbf98500b5316bbccce65eb050b080d' 
  AND token = 'feLqf+EMvmP7hgGMDVYmGJwRvvDXyYRCxUcQxdnG4Zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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