SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6acb6484ce71a6befead3388af0ea2daf4018b9761c429832ebcef9490ba4557' 
  AND token = 'x7URNITPszFZ2liVp2M1zrltfAmPaLf4sfhjZpoU0I4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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