SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04912556e1063379096cbca13b48f2f14efe34d7933eede697615c2d6bc2aa29' 
  AND token = 'rljB/PKFID9XF6TJLo4UUDyG4VqLbjNyZqwJ8mNgq8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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