SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb592c38bb3bd42d99490d17de2c8b8ff2cd0abfc71284a4cd42eeafd0ecfb4f' 
  AND token = 'Xx6mReRkVoTf94W8C40oWKARCqEITirSfi/S/pXusMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}