SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1269a29b8239ec75b7dddd7e64b8ff3f652f1785bf4334acd884d0418dc82b12' 
  AND token = '8dHEYUh4ZfgwIFFUj3u5Az8mBEzUNbfbq0p9G7GKe/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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