SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54652208673c4e9e2984db3f27ac77146d2d325e56f3f23dd57b08bad20a52e' 
  AND token = '3zaRJuAivFiK/WEHnmsdn82A/xwJt+jO3UGVLsX9lNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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