SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98100bb6b161a64382f279cbc588a44ceda5d3ffb0e9d37a3ae36971c33e41b0' 
  AND token = 'B4qZUxXKQksAAdfcPJvBT+etOXVi2WQOz3S1XBrC38o=' 
  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"
    }
  }
}