SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b06287b1ad729529fabcffb05e9a0c98c8f50c6b6958530402c6cdf328845cfe' 
  AND token = 'GK6VGjTaRhQchv5AZNjztYMCU+rTKUC4VZVO+bsByGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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