SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81dd08ff328e31828f4ec20846d044873ea6ad239a5a77f3832921c8684a04fc' 
  AND token = 'yhPX1HLhN6pANXg1az12/7g/xHZoEJvCsutadyXwnUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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