SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '438312e63f4ac486739071f197d00c38dddc50894c16a8b2ecb4a2726163dafb' 
  AND token = 'vlJv6O8xqj3Tgoc/bZC0xSyfV+hrJLlFLohdkvs9sSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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