SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b49d84ad13351a0aea2522f81382a2a0d496e27964edcaa70209c3810bda7861' 
  AND token = 'gwbUJrJQWtYXNSzNcciDZ/v4a6wAH9ryxK2G7ir3C4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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