SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '887724b1231649fc57520a1a8ec35919d19040aec66b592d5d710ff7deb728fd' 
  AND token = 'lOSmapoqulmoTeauyWk99/JBAnlp5iMwlxFWERE+ZXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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