SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5eefe8248b4d4835770d948fe495aaf8031abab90aaef633e7726af7aaada07' 
  AND token = 'JQTbMdI79Mo28pUfDpl6C4EUDKVWzhbYKalfRhYZnSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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