SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51386ada2ecd85e89c79e215a7ad5bac8f36f9fcad17b1f40ebdda396027d076' 
  AND token = 'wVh1yLs5GfF2/IkgLy8enHLeg+5qVBkcsB/qtW66mEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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