SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acecc56ec10ac9394e78f7d4fea08cbf94deb655f2ac17d55a2da518e2042eca' 
  AND token = 'hL+ZswdfEGeydacwRwEgbKOjosZlHK5NA46MpQUGnQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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