SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b66dc16312b89887fa650071cdfc669874420612800f16bc7d9d4a50f632539' 
  AND token = 'jUldZEdUKYsuMfg1YBL9/1Si+pvi5ARfpqsmZaMHraQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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