SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '619e9805844aea7227601d56167582a1e30405f5ebc6227204447122e91068bb' 
  AND token = 'DBE2zKBlsD/ECiicT1dUVdPtcvVtwURK8DOk+lyynpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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