SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba3d33e99f1a1aa9e7c46d9c019b86f0e58f7f5879c2fea2d59ef14072d0b31e' 
  AND token = 'FxXLDWsAZP+7rluLMTkVevWJGshDDau3Y3v9+yCBL1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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