SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20b1ee550159facb5c691366ea35848974eac4252f0f3aac30939431e5a18bb7' 
  AND token = 'gE+3zvg47aR0kGKTJJpVaOul//JpjUi6b8ItHgUzzSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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