SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75fa5dfe6e53a1038fda1a71e506f9786ac048d01d5e9569fac7a09ed336947c' 
  AND token = 'vTw91G+Mf6nDIQQYDsBPQXy8rpeej0cV2sWXTwbn2DQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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