SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb5f396cbe8e3ac03c06801709dcd5f37fd20d45333bd6cf2bdc83a9b86815bb' 
  AND token = 'OjKTJCK78PcFU+R5GXnytY5us8mmKJXJz8YDuxVRrXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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