SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2155f8d5ca3976d52045e3560da1dce1fe469ebdde19247c8572e316ef7325be' 
  AND token = 'tbUeg46TTGCHYN2DImw/xajoFPZe0/kLQhnyKkSOtxY=' 
  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"
    }
  }
}