SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65770bc940a1e62a321ae00646e58a5aa4992553188d01e16cef6a6fd892953a' 
  AND token = 'BNEUl8NBTQekhxtPMlGXf+qL4E3fBJeB3739m8EVsqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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