SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94dd6d5ab42f1a3b7a157108a9fb54576ab07c356234eccd2bbafb48fb62843b' 
  AND token = 'O8ewUMJ4L5rMobWRFvyTPjlkXuAlFIFBVcKmNPUI3PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}