SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61a2c03cff80930c3396a3781c3e42a5e5306f62756c3cc038248bb254be0c8f' 
  AND token = 'Qwz4nFzYBTDgSpW6pqSnTJoji0zs7n4LJZvwdgOv+Hk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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