SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e5610312cee7dce25260c4e0e611c9ac0f5121bec39cd45354cf4d30608e272' 
  AND token = 'e47cfwV2BchZdWZ2gT7GA19GFcKF24vzikEoH+Hfp9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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