SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abc34e4c964a13d9ae5c8841665d5ce58cb2a87405006c4bed8da76039bea732' 
  AND token = 'dB8pnbCrxCfef4qAjeva+K3eb2FBP0Dr5mmqAV4jmMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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