SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5771b203d4231fcb336b04d5244eff0e3f4628caead49f5f1ef16752013563d8' 
  AND token = '/Qrps06G/E1hwOVIXxjsPslnuiDrYrnKlMkhOaBcPPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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