SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b23ac1af7352f2cf6ec992bb18976679dd2984783a76755b70520d52af4f245' 
  AND token = 'CWsZGEWU9u3ybKnV7TC0ipKVHWBEG/Fkrm5wRLC/XYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}